Help regarding encapsulating vBulletin content

[ebonus]

Dear fellow webmasters,
I recently purchased vBulletin and installed it succesfully on my server. I'd like my forum to get integrated into my website, reason why I'm using a standard header and all specific content goes into a middle section. That's what I'd like to do also with vBulletin. To do so, I've modified headers and footers to 'force' all the html code generated by vBulletin to go into this middle section by adding <div> tags.
My problem is, in some cases it works, but in others vBulletin 'closes' the div tag before reaching the footer not encapsulating the content properly.

Example where it works:
http://www.ebonus.es/foro/forumdisplay.php?f=1

Example where it doesn't work:
http://www.ebonus.es/foro/showthread.php?p=1#post1

My question is: How can I instruct vBulletin software not close the div tags?

Alternatively, Is there any other easier method to get the same result?

Is there any technical info or tutorial out there?


Thanks to everyone for your help.